Stoichiometry and Balancing Equations
For each reaction balance the equation first
1) Determine the mass of lithium hydroxide, LiOH, produced when 0.38 g of lithium nitride, Li3N, reacts with water according to the following equation:
Li3N + 3H2O à NH3 + 3LiOH
0.38 g x 1 moles Li3N = 0.0109 moles Li3N
34.833 g
0.0109 moles Li3N x 3 moles LiOH = 0.0327 mole LiOH
1 mole Li3N
0.0327 mole LiOH x 23.941 g = 0.79 g LiOH
1 mole LiOH
2) What mass of sodium chloride, NaCl, is produced when chlorine reacts with 0.29 g of sodium iodide, NaI?
Cl2 + 2NaI à 2NaCl + I2
0.29 g x 1 moles NaI = 0.001934 moles NaI
149.9 g
0.001934 moles NaI x 2 moles NaCl = 0.001934 mole NaCl
2 mole NaI
0.001934 mole NaCl x 58.45 g = 0.11 g NaCl
1 mole NaCl
3) Determine the mass of carbon dioxide, CO2, produced when 0.85 g of butane, C4H10, reacts with oxygen according to the following equation: (Hint to balance you will have to multiply by 2)
2C4H10 + 13O2 à 8CO2 + 10H20
0.85 g x 1 moles C4H10 = 0.01465 moles C4H10
58 g
0.01465 moles C4H10 x 8 mole CO2 = 0.05862 mole CO2
2 mole C4H10
0.05862 mole C4H10 x 44 g = 2.6 g CO2
1 mole CO2
4) Determine the mass of antimony, Sb, produced when 0.46 g of antimony(III) oxide, Sb2O3, reacts with carbon according to the following equation:
Sb2O3 + 3Cà 2Sb + 3CO
0.46 g x 1 moles Sb2O3.01465 = 0.0015775 mole Sb2O3
291.6 g
0.0015775 mole Sb2O3 x 2 mole Sb = 0.003155 mole Sb
1 mole Sb2O3
0.003155 mole Sb x 121.8 g = 0.38 g Sb
1 mole Sb
5) What mass of hydrogen peroxide (H2O2) must decompose to produce 0.77 g of water?
2H2O2 à 2H2O + O2
0.77 g x 1 moles H2O = 0.042777 mole H2O
18.02 g
0.042777 mole H2O x 2 mole H2O2 = 0.042777 mole H2O2
2 mole H2O
0.042777 mole H2O2 x 34.04 g = 1.5 g H2O2
1 mole H2O2
6) What mass of carbon monoxide, CO, must react with oxygen to produce 0.69 g of carbon dioxide, CO2?
2CO + O2 à 2CO2
0.69 g x 1 moles CO2 = 0.01568 mole CO2
44 g
0.01568 mole CO2 x 2 mole CO = 0.01568 mole CO
2 mole CO2
0.01568 mole CO x 28 g = 0.44 g CO
1 mole CO
7) Determine the mass of sodium nitrate, NaNO3, produced when 0.73 g of nickel (II) nitrate, Ni(NO3)2 , reacts with sodium hydroxide according to the following equation:
Ni(NO3)2 + 2NaOHà Ni(OH)2 +2NaNO3
0.73 g x 1 moles Ni(NO3)2 = 0.003998 mole Ni(NO3)2
182.69 g
0.003998 Ni(NO3)2 mole x 2 mole NaNO3 = 0.00799 mole NaNO3
1 mole Ni(NO3)2
0.00799 mole NaNO3 x 85 g = 0.68 g NaNO3
1 mole NaNO3
8) Determine the mass of calcium hydroxide, Ca(OH)2, produced when calcium carbide reacts with 0.64 g of water, H2O, according to the following equation:
CaC2 + 2H2O à Ca(OH)2 + C2H2
0.64 g x 1 moles H2O = 0.0355 mole H2O
18 g
0.0355 H2O mole x 1 mole Ca(OH)2 = 0.01778 mole Ca(OH)2
2 mole H2O
0.01778 mole Ca(OH)2 x 74.1 g = 1.3 g Ca(OH)2
1 mole Ca(OH)2
9) How many grams of ozone (O3) must decompose to produce 0.87 g of oxygen?
2O3 à 3O2
0.87 g x 1 moles O2 = 0.0272 mole H2O
32 g
0.0272 O2 mole x 2 mole O3 = 0.018125 mole O3
3 mole O2
0.018125 mole O3 x 48 g = 0.87 g O3
1 mole O3
10) Find the mass of sugar (C6H12O6) required to produce 1.82 L of carbon dioxide, CO2, gas at STP from the reaction described by the following equation: (Remember 1 mole of gas = 22.4L at STP)
C6H12O6 à 2C2H6O +2CO2
1.82 L x 1 moles CO2 = 0.08125 mole CO2
22.4 L
0.08125 mole CO2 x 1 mole C6H12O6 = 0.040625 mole C6H12O6
2 mole CO2
0.040625 mole C6H12O6 x 180.18 g = 7.32 g C6H12O6
mole C6H12O6
11) How many liters of oxygen are necessary for the combustion of 425 g of sulfur, assuming that the reaction occurs at STP?
The balanced equation is S+ O2 à SO2.
425 g x 1 moles S = 13.25226 mole CO2
32.07 g
13.25226 mole S x 1 mole O2 = 13.25226 mole O2
1 mole S
13.25226 mole O2 x 22.4 L = 297 L O2
1 mole O2
12) Find the mass of benzene (C6H6) required to produce 2.66 L of carbon dioxide, CO2, gas at STP from the reaction described by the following equation: (Hint to balance you will have to multiply by 2)
2C6H6 + 15O2 à 6H2O + 12CO2
2.66 L x 1 moles CO2 = 0.11875 mole CO2
22.4 L
0.11875 mole CO2 x 2 mole C6H6 = 0.01979 mole C6H6
12 mole CO2
0.01979 mole C6H6 x 78.12 g = 1.55 g C6H6
mole C6H6